Background: There has been a substantial improvement in classifying patients with primary Sjögren's syndrome (pSS), with the new 2016 ACR/EULAR classification criteria. It was aimed to investigate the potential role of parotid elastography in the classification of patients with pSS, as well as the clinical diagnosis of those who do not otherwise fulfil the criteria.
Method: This is a cross-sectional analysis of patients with pSS followed up in tertiary out-patient rheumatology clinic. Patients' medical records were retrospectively investigated whether or not clinically diagnosed pSS patients fulfil 2016 ACR/EULAR criteria sets. Elastographic evaluation of parotid and submandibular glands bilaterally was performed when presented for follow-up. Strain ratio, shear wave velocity and Pascal values of the glands were obtained.
Results: Clinical data on 179 patients with Sjögren's syndrome were investigated. Ninety-six patients with pSS and 30 gender and age-matched healthy controls were included in the study. Eighty-six percent of the clinically diagnosed patients satisfied the 2016 ACR /EULAR criteria and were considered 'criteria patients', and the remaining were considered 'non-criteria patients'. Both criteria and non-criteria patients had significantly higher parotid strain ratio and submandibular velocity compared with healthy controls (p < 0.001 and p < 0.001 for parotid strain ratio and p < 0.001 and p = 0.016 for submandibular velocity, respectively). Replacing labial gland biopsy findings with parotid strain ratio in the new classification criteria resulted in similar sensitivity and lower specificity, 91.6% and 80%, respectively.
Conclusion: Parotid shear elastography is an easy and noninvasive method and might be a useful tool for the classification of patients with pSS, especially when labial gland biopsy is not feasible. Key Points • Salivary gland elastography (SGE) is a useful tool for the classification of patients with pSS. • SGE could be performed instead of labial biopsy without changing the diagnostic power of classification criteria.
Keywords: Classification; Elastography; Labial biopsy; Primary Sjögren’s syndrome.